Twist-lock battery pack attachment device

ABSTRACT

An exemplary attachment device includes a twist-lock rotatable from a first position to a second position. The twist-lock in the first position permits movement of a battery array to and from an installed position within a battery pack. The twist-lock in the second position secures the battery array in the installed position.

BACKGROUND

Generally, electrified vehicles differ from conventional motor vehiclesbecause electrified vehicles include one or more electric machinespowered by batteries. The electric machines can selectively drive thevehicle. Conventional motor vehicles, in contrast to electrifiedvehicles, are driven exclusively by an internal combustion engine.Example electrified vehicles include all-electric vehicles, hybridelectric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuelcell vehicles, and battery electric vehicles (BEVs).

A powertrain of an electrified vehicle is typically equipped with abattery pack having battery cells that store electrical power forpowering the electric machine. The battery cells are arranged in arraysof multiple battery cells. The arrays are secured within a case of thebattery pack.

SUMMARY

An attachment device according to an exemplary aspect of the presentdisclosure includes, among other things, a twist-lock rotatable from afirst position to a second position. The twist-lock in the firstposition permits movement of a battery array to and from an installedposition within a battery pack. The twist-lock in the second positionsecures the battery array in the installed position.

In a further non-limiting embodiment of the foregoing device, thetwist-lock in the second position clamps a foot to a tray of the batterypack.

In a further non-limiting embodiment of any of the foregoing devices,the twist-lock is secured to the tray.

In a further non-limiting embodiment of any of the foregoing devices,the twist-lock has an aperture extending along an axis. The aperture isto receive a fastener. The twist-lock is rotatable about the fastenerfrom the first position to the second position.

In a further non-limiting embodiment of any of the foregoing devices,the twist-lock extends from a first end section to an opposing secondend section. The first end section includes a first groove to receive aportion of the battery array when the twist-lock is in the secondposition.

In a further non-limiting embodiment of any of the foregoing devices,the portion is a foot.

In a further non-limiting embodiment of any of the foregoing devices,the battery array is a first battery array, and the second end sectionof the twist-lock includes a second groove to receive a portion of asecond battery array.

In a further non-limiting embodiment of any of the foregoing devices,the first end section terminates at a first end face and the second endsection terminates at a second end face. The twist-lock has a pair ofside surfaces spaced apart from each other. Each of the side surfacesextends from the first end face to the second end face. The first grooveextends from the first end face to one of the side surfaces. The secondgroove extends from the second end face to the other of the sidesurfaces.

In a further non-limiting embodiment of any of the foregoing devices,the first groove tapers away from the first end face and the secondgroove tapers away from the second end face.

In a further non-limiting embodiment of any of the foregoing devices,the device includes a body section joining the first end section and thesecond end section. The body section has an aperture extending along anaxis. The aperture is to receive a fastener. The twist-lock is rotatableabout the fastener from the first position to the second position.

In a further non-limiting embodiment of any of the foregoing devices,the body section includes a boss extending axially past the first endsection in a first direction and axially past the first end section in asecond direction opposite the first direction. The boss provides theaperture.

In a further non-limiting embodiment of any of the foregoing devices,the device includes a plurality of fins extending outward from the boss.

A battery pack assembly according to another exemplary aspect of thepresent disclosure includes, among other things, a battery array, a caseto hold the battery array, and a twist-lock securing the battery arrayto the case.

In a further non-limiting embodiment of the foregoing battery packassembly, the assembly includes a plurality of battery cells and asupport structure to hold the plurality of battery cells. The twist-lockclamps a foot of the support structure when securing the battery arrayto the case.

In a further non-limiting embodiment of any of the foregoing batterypack assemblies, the foot is recessed entirely beneath the batterycells.

In a further non-limiting embodiment of any of the foregoing batterypack assemblies, the twist-lock is rotatable from a first position to asecond position. The twist-lock in the first position permits movementof the battery array to and from an installed position within the case.The twist-lock in the second position secures the battery array in theinstalled position.

A method of securing a battery array according to yet another exemplaryaspect of the present disclosure includes, among other things, securinga twist-lock to a case, and rotating the twist-lock to secure a batteryarray to the case.

In a further non-limiting embodiment of the foregoing method, thesecuring is during the rotating.

In a further non-limiting embodiment of any of the foregoing methods,the battery array is a first battery array and the rotating furthersecures a second battery array to the case.

In a further non-limiting embodiment of any of the foregoing methods,the method includes clamping a foot of the battery array against thecase during the rotating.

The embodiments, examples and alternatives of the preceding paragraphs,the claims, or the following description and drawings, including any oftheir various aspects or respective individual features, may be takenindependently or in any combination. Features described in connectionwith one embodiment are applicable to all embodiments, unless suchfeatures are incompatible.

DESCRIPTION OF THE FIGURES

The various features and advantages of the disclosed examples willbecome apparent to those skilled in the art from the detaileddescription. The figures that accompany the detailed description can bebriefly described as follows:

FIG. 1 is a schematic view of an example electrified vehicle powertrain.

FIG. 2 is a schematic section view of the battery pack of FIG. 1.

FIG. 3 shows a perspective view of an array of the battery pack of FIG.2.

FIG. 4A illustrates a top view of a portion of the battery pack of FIG.2 showing a twist-lock in a first position.

FIG. 4B shows a side view of the portion of the battery pack shown inFIG. 4A.

FIG. 5A shows a top view of the portion of the battery pack of FIG. 2with the twist-lock rotated to a second position.

FIG. 5B shows a side view of the portion of the battery pack shown inFIG. 5A.

FIG. 6 shows a perspective view of another example twist-lock.

FIG. 7 shows a side view of the twist-lock of FIG. 6 within a batterypack.

FIG. 8 shows a perspective view of the twist-lock of FIG. 6 within thebattery pack of FIG. 7.

FIG. 9 shows a bottom view of the twist-lock of FIG. 6.

DETAILED DESCRIPTION

This disclosure relates generally to securing portions of a battery packand, more particularly, to securing arrays of battery cells using atwist-lock device to, among other things, reduce a packaging footprint.

FIG. 1 schematically illustrates a powertrain 10 for a hybrid electricvehicle (HEV). The powertrain 10 includes a battery pack 14, a motor 18,a generator 20, and an internal combustion engine 22.

The motor 18 and generator 20 are types of electric machines. The motor18 and generator 20 may be separate or may have the form of a combinedmotor-generator.

In this embodiment, the powertrain 10 is a power-split powertrain systemthat employs a first drive system and a second drive system. The firstand second drive systems generate torque to drive one or more sets ofvehicle drive wheels 26 of the electric vehicle. The first drive systemincludes a combination of the engine 22 and the generator 20. The seconddrive system includes at least the motor 18, the generator 20, and thebattery pack 14. The motor 18 and the generator 20 are portions of anelectric drive system of the powertrain 10.

The engine 22, which is an internal combustion engine in this example,and the generator 20 may be connected through a power transfer unit 30,such as a planetary gear set. Of course, other types of power transferunits, including other gear sets and transmissions, may be used toconnect the engine 22 to the generator 20. In one non-limitingembodiment, the power transfer unit 30 is a planetary gear set thatincludes a ring gear 32, a sun gear 34, and a carrier assembly 36.

The generator 20 can be driven by engine 22 through the power transferunit 30 to convert kinetic energy to electrical energy. The generator 20can alternatively function as a motor to convert electrical energy intokinetic energy, thereby outputting torque to a shaft 38 connected to thepower transfer unit 30. Because the generator 20 is operativelyconnected to the engine 22, the speed of the engine 22 can be controlledby the generator 20.

The ring gear 32 of the power transfer unit 30 can be connected to ashaft 40, which is connected to vehicle drive wheels 26 through a secondpower transfer unit 44. The second power transfer unit 44 may include agear set having a plurality of gears 46. Other power transfer units mayalso be suitable. The gears 46 transfer torque from the engine 22 to adifferential 48 to ultimately provide traction to the vehicle drivewheels 26. The differential 48 may include a plurality of gears thatenable the transfer of torque to the vehicle drive wheels 26. In thisexample, the second power transfer unit 44 is mechanically coupled to anaxle 50 through the differential 48 to distribute torque to the vehicledrive wheels 26.

The motor 18 can also be employed to drive the vehicle drive wheels 26by outputting torque to a shaft 52 that is also connected to the secondpower transfer unit 44. In one embodiment, the motor 18 and thegenerator 20 cooperate as part of a regenerative braking system in whichboth the motor 18 and the generator 20 can be employed as motors tooutput torque. For example, the motor 18 and the generator 20 can eachoutput electrical power to the battery pack 14.

Referring now to FIGS. 2 to 5B, the example battery pack 14 provides arelatively high-voltage battery that stores generated electrical powerand outputs electrical power to operate the motor 18, the generator 20,or both.

The battery pack 14 includes a plurality of arrays 60. Each of thearrays 60 includes a plurality of individual battery cells 64 heldwithin a support structure 68. The battery cells 64 are distributedalong an axis A. The support structure 68 can includes a frame about theperimeter of each of the battery cells 64. The support structure 68 canfurther include end walls 68′.

The battery cells 64 and support structure 68 are disposed on a coldplate 70. A coolant circulates through channels within the supportstructure 68 to carry thermal energy from the arrays 60.

The battery pack 14 includes a case 74 that houses the battery arrays60. The case includes a lid 78 secured to a floor 82.

A plurality of twist-locks 86 secure the battery arrays 60 within thecase 74. The example twist-locks 86 are attached directly to the floor82. The twist-locks 86 are rotatable from a first position shown inFIGS. 4A and 4B to a second position shown in FIGS. 2, 5A, and 5B.

The battery arrays 60 are free to move relative to the floor 82 when thetwist-locks 86 are in the first position. That is, the twist-locks 86 donot secure the battery arrays 60 when the twist-locks 86 are in thefirst position.

Rotating the twist-locks 86 to the second position secures the batteryarray 60 in an installed position within the case 74. In the installedposition, the battery array 60 is in a final position within the case74. The lid 78 and the floor 82 can then be secured, and the entirebattery pack 14 secured to a vehicle.

In this example, the twist-locks 86 secure the battery arrays 60 to thefloor 82. In another example, the twist-locks 86 secure the batteryarrays 60 to another portion of the battery pack 14, such as the lid 78,or both the floor 82 and the lid 78.

Each of the example twist-locks 86 are secured to the floor 82 with afastener 90. In this example, the twist-locks 86 are rotated between thefirst position and the second position during the securing of thefastener 90. In another example, the twist-locks 86 are moved betweenthe first position and the second position by a tool or by hand. Whenthe fastener 90 is fully seated an secured, twist-locks 86 in the secondposition cannot move back to the first position due to, for example,frictional forces between the fastener 90 and the twist-lock 86. If thefastener 90 is loosened, the twist-lock 86 can be moved back to thefirst position.

In general, twist-locks 86 include devices that rotate less than 360degrees to move back and forth between a locking position and anunlocked position. In the example embodiment, the twist-locks 86 rotate90 degrees to move back and forth between a locking position and anunlocked position. The twist lock 86 can be restricted in position by apositive stopper, which allows for adjusting the desired stop position.

To secure the arrays 60 within the battery pack 14, the exampletwist-locks 86, in a locking position, clamp a foot 94 of the supportstructure 68 against the floor 82 when the twist-locks 86 are in theinstalled position. Notably, the foot 94 of the example supportstructure 68 is recessed and does not extend laterally past a laterallyoutermost edge 98 of the arrays 60. Thus, the foot 94 does not requirepackaging space laterally beyond the outermost edge 98 of the supportstructure 68.

The twist-lock 86 has a width W_(TL) that is less than a width W_(G) ofa gap G between the battery array 60 and an adjacent battery array 60.This facilitates moving the twist-lock 86 to an installed positionwithin the battery pack 14.

During assembly, the battery arrays 60 are placed on the floor 82. Thetwist-locks 86 are then moved downward within the gap G to the floor 82.The twist-locks 86 could also be placed on the floor 82 prior to thebattery arrays 60 to assist in positioning the battery arrays 60. Atool, such as a torque gun, is then moved into the gap G. The toolrotates the fastener 90 to secure the twist-lock 86 to the floor 82.

Rotating the fastener 90 also causes the twist-lock 86 to rotate fromthe first position to the second position, which clamps the foot 94against the floor 82 and secures the battery array 60 in the installedposition.

As shown in at least FIG. 2, some of the twist-locks 86 can secure thefeet 94 of two separate arrays 60. Other twist-locks 86 can secure thefoot 94 of one of the arrays 60.

Referring now to FIGS. 6 to 9, another example twist-lock 100 suitablefor use in the battery pack 14 of FIG. 1 includes a first end section104 and a second end section 108 extending from opposing sides of a bodysection 112. The first end section 104 terminates at a first end face120 and the second end section 108 terminates at a second end face 124.

The twist-lock 100 further includes side surfaces 128 and 132 extendingfrom the first end face 120 to the second end face 124. Portions of theside surfaces 128 and 132 are provided by the first end section 104, thesecond end section 108, and the body section 112.

The example body section 112 has an aperture 140 along an axis B. Theaperture 140 receives the fastener 90 to secure the twist-lock 100 tothe floor 82 of the battery pack 14.

A boss 144 of the main body section 112 provides the aperture 140 inthis example. Fins 148 extend outwardly away from the boss 144perpendicular to the axis B. In other examples, the fins do not extendradially from the boss 144. In this example, the boss 144 and the fins148 extend axially past both the first end section 104 and the secondend section 108.

The example twist-lock 100 includes a first groove 150 and a secondgroove 154. The first groove 150 extends across the first end face 120to the side surface 132. The second groove 154 extends across the secondend face 124 to the side surface 128. The dimensions of the grooves 150and 154 are substantially the same. Along the first end face 120, theheight of groove 150 is relatively consistent. Along the second end face124, the height of the groove 154 is relatively consistent. Along theside 132, and optionally a portion of the end face 120, the first groove150 tapers away from the first end face 120. The second groove 154tapers away from the second end face 124. Along the side 132, andoptionally a portion of the end face 120, the first groove 150 tapersaway from the first end face 120.

The tapering of the grooves 150 and 154 facilitates movement of thetwist-lock 100 from the first position to the second position. Withrespect to the groove 154, as the twist-lock 100 is rotated in adirection D from the first position to the second position, thetwist-lock 100 first contacts the twist-lock 100 near a start 158 of thegroove 154. As the twist-lock 100 continues to rotate, the foot F rideswithin the groove 154 along a downwardly facing surface 166 of thetwist-lock 100. The angling of the surface 166 facilitates engaging fromthe first position to the second position.

In this example, the fastener 90 comprises a nut 160 and a bolt 162. Thenut 160 is secured to the bolt 162 to both secure the twist-lock 100 tothe floor 82 and rotate the twist-lock 100 from the first position tothe second position.

The torque gun is used to rotate the nut 160 relative to the bolt 162.Rotating the nut 160 causes rotation of the twist-lock 100 from thefirst position to the second position. Contact between the foot F andthe first end face within the groove 150 and the second end face 124within the groove 154 prevents the twist-lock 100 from continuing torotate past the second position.

The nut 160 may be a hex nut with a flange where the top of thetwist-lock 100 is overmolded onto the bottom and sides of the nutflange. This allows the twist-lock 100 to retain the nut 160 in acaptured fashion to simplify assembly. It also will tend to ensure thetwist-lock 100 is rotating as the nut 160 is driven down. However, oncethe twist-lock end faces 150 and 154 are driven low enough during thesecure operation to contact the “toe” of the foot 94, the resistancetorque developed by this contact will cause the slightly over molded nut160 to break free from the overmolded plastic and allow the nut 160 tocontinue to rotate down until the twist lock 100 is secured in place.This approach ensures that the twist-lock 100 is rotated until it fullyengages the foot 94 rather than have the rotational motion prematurelyarrested (before it has rotated the proper amount) due to frictiondeveloped between the bottom of the twist-lock 100 and the top of thetray 82. In this example, the twist-lock 100 fully engages the foot 94when the first end face 120 and the second end face 124 are aligned witha respective foot 94.

Features of this invention include an attachment device that secures abattery array within a battery pack without requiring a component of thebattery cells sticking out laterally beyond the battery cells.

Although the battery pack 14 is depicted as within an HEV, it should beunderstood that the concepts described herein are not limited to HEVsand could extend to vehicles, including other electrified vehicles, suchas plug-in hybrid electric vehicles (PHEVs) and battery electricvehicles (BEVs).

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthe essence of this disclosure. Thus, the scope of legal protectiongiven to this disclosure can only be determined by studying thefollowing claims.

We claim:
 1. An attachment device, comprising: a twist-lock rotatablefrom a first position to a second position, the twist-lock in the firstposition permitting movement of a battery array to and from an installedposition within a battery pack, the twist-lock in the second positionsecuring the battery array in the installed position by clamping aportion of the battery array between the twist-lock and a case of thebattery pack.
 2. An attachment device, comprising: a twist-lockrotatable from a first position to a second position, the twist-lock inthe first position permitting movement of a battery array to and from aninstalled position within a battery pack, the twist-lock in the secondposition securing the battery array in the installed position byclamping a foot to a tray of the battery pack.
 3. The attachment deviceof claim 2, wherein the twist-lock is secured to the tray.
 4. Theattachment device of claim 1, wherein the twist-lock has an apertureextending along an axis, the aperture to receive a fastener, and thetwist-lock rotatable about the fastener from the first position to thesecond position.
 5. The attachment device of claim 1, wherein thetwist-lock extends from a first end section to an opposing second endsection, the first end section including a first groove to receive theportion of the battery array when the twist-lock is in the secondposition.
 6. The attachment device of claim 5, wherein the portion is afoot.
 7. The attachment device of claim 6, wherein the battery array isa first battery array, and the second end section of the twist-lockincludes a second groove to receive a portion of a second battery array.8. The attachment device of claim 7, wherein the first end sectionterminates at a first end face and the second end section terminates ata second end face, the twist-lock having a pair of side surfaces spacedapart from each other, each of the side surfaces extending from thefirst end face to the second end face, the first groove extending fromthe first end face to one of the side surfaces, the second grooveextending from the second end face to the other of the side surfaces. 9.The attachment device of claim 8, wherein the first groove tapers awayfrom the first end face and the second groove tapers away from thesecond end face.
 10. The attachment device of claim 5, comprising a bodysection joining the first end section and the second end section, thebody section having an aperture extending along an axis, the aperture toreceive a fastener and the twist-lock rotatable about the fastener fromthe first position to the second position.
 11. The attachment device ofclaim 10, wherein the body section includes a boss extending axiallypast the first end section in a first direction and axially past thefirst end section in a second direction opposite the first direction,the boss providing the aperture.
 12. The attachment device of claim 11,comprising a plurality of fins extending outward from the boss.
 13. Abattery pack assembly comprising the attachment device of claim 1 andfurther comprising: a case of the battery pack to hold the batteryarray, wherein the twist-lock in the second position secures the batteryarray to the case.
 14. The battery pack assembly of claim 13, comprisinga plurality of battery cells and a support structure to hold theplurality of battery cells, the twist-lock clamping a foot of thesupport structure when securing the battery array to the case.
 15. Thebattery pack assembly of claim 14, wherein the foot is recessed entirelybeneath the battery cells.
 16. The battery pack assembly of claim 13,wherein the twist-lock is rotatable from a first position to a secondposition, the twist-lock in the first position permitting movement ofthe battery array to and from an installed position within the case, thetwist-lock in the second position securing the battery array in theinstalled position.
 17. A battery assembly, comprising: a battery arrayof a battery pack; and a twist-lock rotatable from a first position to asecond position, the twist-lock in the first position permittingmovement of the battery array to and from an installed position withinthe battery pack, the twist-lock in the second position clamping aportion of the battery array to a case of the battery pack in theinstalled position.
 18. The battery assembly of claim 17, comprising thecase of the battery pack, the twist-lock securing the battery array tothe case when the twist-lock is in the second position.
 19. The batteryassembly of claim 18, comprising a tray of the case, wherein the portionof the battery array is a foot of the battery array that is clamped tothe tray when the twist-lock is in the second position.